The present invention relates to a system and method for distributing power to circuit elements, and more specifically, to a central current source which is commutated among a number of energy storage devices, such as capacitors, which function as independent power sources.
There are electrical applications in which a number of independent and varying power supplies are necessary. For instance, in printed circuit boards, there are usually a variety of components and sub-circuits which require independent power supplies. Separate power supplies are required for a variety of reasons, such as varying voltage requirements, noise and isolation concerns, etc. Generally, the voltage requirements in integrated circuits are relatively small, ranging between 5 volts to 0.50 volts. In light of the low operational voltages of such circuits, voltage deviations on the power supply line due to phenomena such as source variations, load variations, and electrical noise, can be a significant portion of the output voltage and can cause operational problems. Also, given the trend of electronic circuits becoming smaller in physical dimensions, it is becoming increasingly impractical to use multiple power supplies which would limit the extent to which printed circuit boards can be reduced in size.
Therefore, there is a need for a power distribution system and method which can be utilized to provide separately regulated power to multiple loads with a variety of voltage requirements while reducing the number of required power supplies.
Accordingly, an object of the present invention is to provide a novel power distribution system and method in which a single power source can distribute power to multiple loads with varying voltage requirements.
Another object of the present invention is to provide a novel power distribution system and method in which the reliability of the individual load output voltages is enhanced by reducing electrical noise and interference.
A further object of the present invention is to provide a novel power distribution system which will increase power efficiency.
In accordance with one embodiment of the present invention, all of these objects, as well as others not herein specifically identified, are achieved generally by the present power distribution system and method in which a centralized current source is commutated among multiple energy storage devices, such as capacitors, which are connected in parallel with their respective loads.
More specifically, one embodiment of the present invention includes a switching regulated current source which is sequentially connected in parallel circuit arrangement with a number of load capacitors, each capacitor being connected to the current source through a switch. Each capacitor is connected to a load and can be charged to predetermined voltages during its charging time slot, thereby providing power to each load. The capacitors can be charged to varying voltages, allowing for a single current source to provide a number of output load voltages. The frequency and duration of the switch operations can be varied to enhance efficiency of the power distribution or to accommodate the particular requirements of the electrical system. Further, additional circuit arrangements can be utilized to enhance the efficiency and enhance isolation of each distribution circuit.
Because a significant portion of a switching regulator""s power losses are independent of load, this approach achieves higher efficiency as well as smaller size in comparison to using multiple individual power supplies for each output voltage requirement.